Improve comment and error text formatting

Author: rdettai

quickwit/quickwit-serve/src/elasticsearch_api/bulk_v2.rs

@@ -123,7 +123,7 @@ pub(crate) async fn elastic_bulk_ingest_v2(
                 )
             })?;
 
-        // Validate index id early because propagating back the right error (400)
+        // Validate index ID early because propagating back the right error (400)
         // from deeper ingest layers is harder
         if validate_identifier("", &index_id).is_err() {
             let invalid_item = make_invalid_index_id_item(index_id.clone(), meta.es_doc_id);

quickwit/quickwit-serve/src/ingest_api/rest_handler.rs

@@ -215,11 +215,11 @@ async fn ingest_v2(
         None
     };
 
-    // Validate index id early because propagating back the right error (400)
+    // Validate index ID early because propagating back the right error (400)
     // from deeper ingest layers is harder
     if validate_identifier("", &index_id).is_err() {
         return Err(IngestServiceError::BadRequest(
-            "invalid index_id".to_string(),
+            "invalid index ID".to_string(),
         ));
     }